Heretofore, coating compositions, such as latex paints containing pyrithione (typically in the form of zinc pyrithione) to provide antimicrobial protection of the paint in its "dry film" form after use, also generally require the presence of a supplemental antimicrobial additive, such as a hydrazine derivative, to provide "in-can" preservation of the paint against microbial (notably bacterial) attack during in-can storage of the paint prior to use. Unfortunately, these hydrazine derivative in-can preservatives are formaldehyde releasers, which poses a threat from an environmental, health and toxicity standpoint. New solutions to this problem must be found, particularly in view of the stringent air-quality standards required by the Clean Air Act of 1990.
Accordingly, there has been a recent push in the industry to satisfy a long-felt need for antimicrobial additives that provide a combination of effective in-can preservation and antimicrobial protection of the dry film coating without release of formaldehyde. The present invention provides one answer to this long-felt need.